求解数学题额````

显示全部楼层 · 2009-7-3 21:22:02

3a2+ab-2b2=0(3a-2b)(a+b)=0所以3a-2b=0,a+b=03a=2b,a=-b所以b/a=3/2或-1a/b-b/a-(a2+b2)/ab=(a2-b2)/ab-(a2+b2)/ab=(a2-b2-a2-b2)/ab=-2b2/ab=-2b/a=-2*（3/2）=-3或=-2*(-1)=2...

千问 · 2009-7-3 21:22:02

3a2+ab-2b2=(3a-2b)(a+b)=03a-2b=0 或 a+b=0所以 a=2b/3 或a=-b1) a=2b/3时,a/b-b/a-(a2+b2)/ab=2/3-3/2-(4/9+1)/(2/3)=-5/6 -13/6=-3 2)a=-b时a/b-b/a-(a2+b2)/ab=-1-(-1)-2/(-1)=2...